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U S. p. R. R EXP. AND SURVEYS — ZOOLOGY — GENERAL RtPORT. 



Selasphorus. — Feathers of the throat much elongated laterally into a ruff. Lateral tail 

 feathers much narrower than the middle ones, and linear in shape, or with the sides 

 parallel to the end, which is rounded. Tail graduated or cuneate. Outer primary- 

 attenuated at the tip. Crown without red metallic scales. 

 Atthis. — Similar to the last, but the top of the head with metallic scales like the throat. 

 The outer primary not attenuated. Tail emarginated or deeply forked. 

 The following table exhibits the comparative measurements of the different North American 

 species of humming bird : 



Comparative measurements of species. 



LAMPORNIS, Swain son. 



Lampornis, Swainson, Zoological Journal, 1827, 358. 



The single species of this genus assigned to the United States is readily distinguished by its 

 generic characters from any other belonging to the same region. 



LAMPORNIS MANGO, Swainson. 



Black-throated Hnmmiug Bird. 



Trochilits mango, Linn. Syst. Nat. I, 1766, 171. — Audubon, Orn. Biog. II, 1834, 486 ; pi. 184. — Ib. Birds America, 



IV, 1842, 186 i pi. 251. 

 Lampornis mango, Swainson, Zool. Journal, 1827, 358. 



Above and on the sidea metallic green and golden. Beneath opaque velvety bluish black, this color narrowed on the breast 

 by the encroachment of the green of tlie sides. Upper surface of wings and tail purplish black ; the latter with greenish 

 reflections. All the tail feathers except the innermost purplish violet, abruptly margined with blackish. A tuft of downy 

 white feathers under the wings, and around the tibia. 



Female quite similar, the black of the under parts replaced by while, with a narrow stripe of black down the niidalo of the 

 hroat and belly. Length 4 50 inches ; wing 2.60 ; tail 1.7 



The female of this species is quite similar to the male, except as described. The tail is 



